How to test
The Guideline notes that none of the available endoscopic and nonendoscopic testing options “can be considered the gold standard” and recommends choice based on clinical indications, infection prevalence, availability, and cost. In the primary-care setting, this nearly always comes down to one of the nonendoscopic procedures: antibody testing, urea breath test (UBT), or fecal antigen test (FAT).
“In practice, most clinicians tend to do serology: Testing is cheap and widely available, and its negative predictive value is good,” Dr. Chey says. “The bad news is that the positive predictive value is terrible.” In areas where prevalence is low (e.g., 20% or below), the Guideline points out, a positive finding in a patient with dyspepsia is “no better than a coin toss.”
UBT and FAT are considerably more accurate. Particularly where prevalence is low, these should be chosen at the outset if readily available or done to confirm a positive antibody test, Dr. Chey says.
Clinicians should remember that the accuracy of UBT and FAT may be compromised by concurrent treatment with a proton-pump inhibitor (PPI), and the patient should be off such drugs for at least a week before testing. Serology is unaffected by PPI treatment and may be a good option for patients with upper GI bleeding, particularly because the pretest probability of infection is high in this group.
Treatment
The Guideline recommends two primary regimens for
H. pylori infection: clarithromycin-based triple therapy (a PPI, clarithromycin, and amoxicillin or metronidazole) for 14 days and bismuth quadruple therapy (a PPI or H2-receptor agonist, bismuth, metronidazole, and tetracycline) for 10-14 days. The regimens have comparable success in eradicating H. pylori (75%-80%).
Primary-care physicians tend to focus inordinately on clarithromycin triple therapy, Dr. Chey indicates. “[They] need to realize that quadruple therapy is on an equal footing” and that the rising incidence of clarithromycin resistance makes quadruple therapy an attractive option in many cases. “Always ask whether the patient has received any macrolide antibiotic within the past five years. If so, he or she is much more likely to have a clarithromycin-resistant strain of
H. pylori.”
To optimize efficacy of clarithromycin triple therapy, the authors say, a full 14-day course is essential; they also note that twice-daily dosing of the PPI appears to be more effective than once-daily dosing.
Among the drawbacks of bismuth quadruple therapy are the complexity of the regimen and frequency of adverse effects. The latter consideration may be less important than it appears: While minor side effects are indeed common, moderate-to-severe difficulties are no more frequent than with triple therapy.
In light of declining efficacy of both standard regimens, alternative treatments have received increasing attention. The Guideline mentions “sequential” therapy as one such possibility: five days of a PPI and amoxicillin, followed by five days of the PPI, clarithromycin, and tinidazole. This regimen was more efficacious than clarithromycin-based triple therapy in some studies abroad, but it hasn't been validated in North America and cannot be recommended as first-line therapy, the authors say.
Retesting
While universal testing to prove eradication of H. pylori after antibiotic treatment is not cost-effective, the current Guideline recommends such testing in circumstances broader than those listed in the earlier document. Candidates now include individuals whose dyspeptic symptoms persist despite testing and treatment, along with patients who have an
H. pylori-associated ulcer or MALT lymphoma and those who have undergone resection of early gastric cancer.
Retesting should be deferred until four weeks after treatment completion; among nonendoscopic tests, UBT is preferred. Persistent infection indicates the need for retreatment with a different antibiotic regimen.
The American College of Gastroenterology
Guideline on the Management of Helicobacter pylori Infection was published in the
American Journal of Gastroenterology (2007;102:1808-1825).
Mr. Sherman is a medical writer in New York City.